1. Field of the Invention
The present invention relates to a method and apparatus to reduce the time period from a power on status to a ready status of a hard disk drive device.
2. Description of Related Art
FIG. 1 is a flow chart describing the operation of a conventional hard disk drive device. The operation starts at step 1 in which a power-on reset (POR) operation is performed in response to the power on of the hard disk drive device. At step 2, an MPU contained in the hard disk drive device starts its operation by using control programs stored in its read-only memory (ROM). Next, at step 3, the rotation of a spindle motor which is coupled to a magnetic recording disk is started. Then, at step 4, the MPU determines whether or not the rotational speed of the spindle motor and the magnetic recording disk reach a final rotational speed, for example 7200 rpm. If the final rotational speed is not met, then the operation returns to step 3, otherwise, the operation proceeds to step 5 in which a supporting arm for supporting a head/slider assembly is moved from a rest position to a position above a data track of the magnetic recording disk by a voice coil motor.
Then at step 6 control programs stored in special data tracks (i.e., outside the data tracks used during normal read/write operations) on the magnetic recording disk are read and stored in random access memory (RAM), and the MPU sends a ready signal to a host processor. At step 7, the hard disk drive device waits for a command from the host processor.
The amount of time for a conventional hard disk drive device to perform the steps described in steps 1-6 (i.e., to transition from a power-on status to a ready status) is relatively long, for example 10 seconds. Moreover, the steps described in steps 1-4 require about 90% of the total time to transition from the power-on status to the ready status.
One approach to reduce the time period from the power-on to the start of the ready status is to increase the current applied to the spindle motor. However, this approach raises a problem that a large current is required during the POR. Furthermore, this approach does not sufficiently reduce the time period.